The 'Fools Gold' band were forced to cut their show short after the drummer departed the venue before the expected encore.
One fan at the concert has claimed that Reni seemed distressed on stage, pointing to the sound mixer.
Paul Roberts told BBC 6Music: "At one point I saw Reni waving his arms wildly at the stage mixer, obviously not happy with something."
BBC journalist Peter Shuttleworth, also at the gig, said he saw Reni hug guitarist John Squire before leaving - appearing to dispel rumours that the 48-year-old stormed out.
After Reni's departure, Ian Brown returned to the stage where he called Reni a "c**t" in front of the disappointed fans, who were expecting the Madchester band to finish with 'I Am the Resurrection'.
However, a Roses spokesperson has since denied reports of a rift between drummer and frontman Brown.
Watch Ian Brown call Reni a c**t in the video below: